MKV Playback on Chrome with Title Versioning

[dudechill8D]

I have recently discovered a strange issue that I believe to be a bug.

The way I have my library set up, I have MKVs of each film, and these files have the original encoding that the original copy had. I have another version that I have re-encoded to be more likely compatible with the devices I use and use less bandwidth/storage. I have gotten my library set up correctly so that these versions are listed under the same title.

If one of these MKVs is under it's own title (with no other versions sharing it) transcoding works perfectly on all devices.

If the MKV is under the same title as another version I have re-encoded and I try to play the MKV, jellyfin for chrome gets stuck trying to load. But this problem doesn't exist for Firefox. I have updated my browsers. I am on linux, but I tried edge in windows 11, and it has the same problem as chrome (makes sense). Also, it is only the case for most of my MKVs, but not all of them.

I have turned on debug mode and collected logs for Firefox and Chrome when a particular MKV is and isn't sharing the same title with another video file. I deleted logs for before and in-between tests for reading convenience. (This problem is very consistently reproducable for me)


  Jellyfin-MKV-Playback-Debug-Logs.zip (Size: 92.29 KB / Downloads: 14)

Edit 2: I probably should have provided a verbose chrome console log. Here it is: 
  Chrome-Console-Log.zip (Size: 17.25 KB / Downloads: 13)

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I am running server, web, and build version 10.11.3, and it is on a fresh install of debian trixie. I am using the debian repo. I tried setting up hardware acceleration after encountering this problem because I think I read somewhere that it had a small chance to fix random transcoding issues (source lost) but didn't succeed in doing so. But I'll leave that to a different thread if I care enough.10.11.310.11.3

What I expect: When an MKV has it's own title, there are options to select the audio track and subtitle track. But when selecting it as an alternate version, those options don't show up before I press play or in the player like they usually do. I'm not sure if this would change if the MKV were made the default (which if more testing is needed, I can try that). My best guess for it breaking on only most of my MKVs is maybe something to do with subtitles? I really have no idea though, just a wild guess. Should I post this to github? I'm hesitant because I've never done that before. If this is ok too or this problem is due to my ignorance, then great.

Edit: I should add that the same behavior exists on jellyfin for android (although expected because I'm pretty sure that's just a web app). In findroid, it plays, but only the audio, the video is just a black screen. And on a Samsung tv we have, it works just fine in the internet app.

[dudechill8D]

Update: It works fine IF the mkv is the first one alphabetically. Where before, selecting the mkv when it wasn't the first one would result in video stats not displaying, but now they do. And it doesn't break anymore. But it would be nice to default to a lower quality, I did this intentionally.

Versioned and alphabetically first: link
Versioned and alphabetically not first: link

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I tried looking at the logs myself and was comparing the ffmpeg logs for when the version did and didn't share a title. I noticed that the transcoding was different.

Transcoding without multi-versioned title:

Code:

...
Stream mapping:
  Stream #0:0 -> #0:0 (mpeg2video (native) -> h264 (h264_qsv))
  Stream #0:1 -> #0:1 (ac3 (native) -> aac (libfdk_aac))
...
Output #0, hls, to '/var/cache/jellyfin/transcodes/0f4366a51a5380737e945109717fa8c5.m3u8':
  Metadata:
    encoder        : Lavf61.7.100
  Stream #0:0: Video: h264, qsv(tv, bt709, progressive), 720x480 [SAR 853:720 DAR 853:480], q=2-31, 6325 kb/s, 29.97 fps, 30k tbn
      Metadata:
        encoder        : Lavc61.19.101 h264_qsv
      Side data:
        cpb: bitrate max/min/avg: 6325942/0/6325941 buffer size: 25303764 vbv_delay: N/A
  Stream #0:1: Audio: aac, 48000 Hz, stereo, s16, 256 kb/s (default)
      Metadata:
        encoder        : Lavc61.19.101 libfdk_aac
      Side data:
        cpb: bitrate max/min/avg: 256000/256000/256000 buffer size: 0 vbv_delay: N/A
...

Transcoding with multi-versioned title:

Code:

...
Stream mapping:
  Stream #0:0 -> #0:0 (mpeg2video (native) -> h264 (libx264))
  Stream #0:1 -> #0:1 (ac3 (native) -> aac (native))
...
Output #0, hls, to '/var/cache/jellyfin/transcodes/5edc49ff4fc8838ee86e9cb330ac56b2.m3u8':
  Metadata:
    encoder        : Lavf61.7.100
  Stream #0:0: Video: h264, yuv420p(tv, progressive), 720x480 [SAR 853:720 DAR 853:480], q=2-31, 29.97 fps, 30k tbn
      Metadata:
        encoder        : Lavc61.19.101 libx264
      Side data:
        cpb: bitrate max/min/avg: 0/0/0 buffer size: 0 vbv_delay: N/A
  Stream #0:1: Audio: aac (LC), 48000 Hz, 5.1(side), fltp, 394 kb/s (default)
      Metadata:
        encoder        : Lavc61.19.101 aac
...

It looks like both video and audio are being transcoded differently. Idk what really any of this means except for 5.1. I did a quick google search and chrome doesn't support 5.1 audio so maybe thats the reason for this case? I have a feeling that the problem is deeper than simply this though. But i did go through a few other mkv movies, and so far the ones that have stereo sound don't have this problem, but ones with 5.1 sound do.